Fuse is blowing for no apparent reason

[Little Song]

Hi all.

Sorry for such a simple question, but my electricity/electronics knowledge is near-zero...

I have a 2003 Beneteau Oceanis 311 Clipper. Yesterday, when switching on the water pump in the switch panel the red light did not turned on. I opened the panel and found out that the 10A fuse was blown out. So I changed the fuse and, when switching on again, the fuse just blown out immediately again.

So, my question is... from where I start and what should I do?...

Thank you very much in advance.
Jorge

[goboatingnow]

Pump could be dead , wires shorted.

[thomm225]

Well first off fuses don't blow for no reason.

To troubleshoot you'll need to know everything that is powered from the power/current that passes thru that fuse.

You can then start unhooking things (loads) one at a time until the fuse stops blowing or unhook everything then test.

Fuse shouldn't blow.

Then add one thing at a time until it blows and that will be your problem.

If you have a terminal board between the loads and the fuse that's even better because you can disconnect from there and test

[mochifanta]

What goboatingnow said. Get a multimeter to test for the short after making sure the pump isn’t jammed. Here is a good YouTube video to give a high level explanation of how to go about troubleshooting.

https://youtu.be/UdDwaWsT3jQ

[mjscottinnc]

I had a bulge pump that would occasionally blow fuses. Everything checked out fine, cleaned out the intake screen multiple times, it ran fine when directly connected. Replaced the float switch, check the wires 4 times. Finally after replacing everything else, replaced the pump. Never had another problem. It wasn’t an obvious failure, on time maybe, temperature maybe, transient short in the windings. Food for thought

[thomm225]

Originally Posted by mochifanta

What goboatingnow said. Get a multimeter to test for the short after making sure the pump isn’t jammed. Here is a good YouTube video to give a high level explanation of how to go about troubleshooting.

https://youtu.be/UdDwaWsT3jQ

Actually you already know there is a short of some sort so no meter needed to tell you that, but you have to disconnect the loads to find it.

If it is one of the loads which it usually is or possibly a pinched wire or a wire that has rubbed it's insulation off and is shorting to something.

Sometimes I have had to find the short with 30-40 loads that are pulling down one power supply. Fuse didn't blow in this case because the current overload immediately shut down the power supply.

I used the same method I mentioned above.

Disconnected all loads to that power supply at the terminal board a few at a time until I found out which one was pulling it down. Problem was a pinched wire on a metal pullout drawer/chassis about 30' away. Fixed that and no more problem

If you don't have a terminal board, disconnect where you can and test.

[mochifanta]

Originally Posted by thomm225

Actually you already know there is a short of some sort so no meter needed to tell you that, but you have to disconnect the loads to find it.

If it is one of the loads which it usually is or possibly a pinched wire or a wire that has rubbed it's insulation off and is shorting to something.

Sometimes I have had to find the short with 30-40 loads that are pulling down one power supply. Fuse didn't blow in this case because the current overload immediately shut down the power supply.

I used the same method I mentioned above.

Disconnected all loads to that power supply at the terminal board a few at a time until I found out which one was pulling it down. Problem was a pinched wire on a metal pullout drawer/chassis about 30' away. Fixed that and no more problem

If you don't have a terminal board, disconnect where you can and test.

Meter helps with wiring faults, etc., but is not strictly necessary as you pointed out, but certainly helpful to have and know how to use.

You can always keep blowing fuses and/or looking for smoke until you figure it out. :-)

[s/v Jedi]

Originally Posted by Little Song

Hi all.

Sorry for such a simple question, but my electricity/electronics knowledge is near-zero...

I have a 2003 Beneteau Oceanis 311 Clipper. Yesterday, when switching on the water pump in the switch panel the red light did not turned on. I opened the panel and found out that the 10A fuse was blown out. So I changed the fuse and, when switching on again, the fuse just blown out immediately again.

So, my question is... from where I start and what should I do?...

Thank you very much in advance.
Jorge

Time to replace the pump with your spare and see if everything turns back to normal

If it doesn’t, report back and we’ll take the next steps.

[Rumrace]

The pump is likely gone. Replace it and add an accumulator if the ex owner didn’t.
Fuses always blow with good reason and and pump can short itself at the armature. Like a dying starter motor then can get so hot they will push solder out.

[team karst]

Since its a water pump, a seized shaft is very possible. Lots of other possibilities, but the top two both require a new pump. I've lost count on the number of DMM's I have, but its not the tool I would initially use to debug this one.
ie; disconnect the pump, see if the fuse holds, if so: replace the pump...

[smac999]

Disconnect the pump from the wires. Put a new fuse in. If it blows you have a damaged wire. If it doesn’t blow. You have a bad pump.

[Little Song]

Hi All.

Thank you for your help and words of wisdom. Tomorrow, I will go try to fix this issue and will post here again.

[coopec43]

I assume the water pump is a diaphragm pump? Have you tried turning the pump shaft to see if it is seized?

https://www.canalworld.net/forums/in...on-water-pump/

fuse keeps blowing

https://forums.iboats.com/threads/bi...-fuses.114546/

https://www.youtube.com/watch?v=V1cwk2fBBHM

[Little Song]

Thank you all for your comments that helped me to solve this problem.

I've disconnected the wiring from the pump and the fuse on the switch panel kept its good health!

Then I took the pump out and tested directly on the battery which sparkled, so the short circuit problem was indeed on the pump.

After dismantling the pump I found two problems. A bit of water (some drops) where it shouldn't be, leaked through the membrane, and the bearing was somewhat stuck. I replaced the bearing and now the pump is working fine.

8.31 Eur and your words of wisdom solved the problem! Thanks!!!

[s/v Jedi]

Originally Posted by Little Song

Thank you all for your comments that helped me to solve this problem.

I've disconnected the wiring from the pump and the fuse on the switch panel kept its good health!

Then I took the pump out and tested directly on the battery which sparkled, so the short circuit problem was indeed on the pump.

After dismantling the pump I found two problems. A bit of water (some drops) where it shouldn't be, leaked through the membrane, and the bearing was somewhat stuck. I replaced the bearing and now the pump is working fine.

8.31 Eur and your words of wisdom solved the problem! Thanks!!!

Buy a spare pump so you can quickly swap, then take your time fixing the pump and put it back to the spares inventory.